Process for preparing azines

ABSTRACT

AZINES ARE PREPARED BY REACTING CHLORINE, DILUTED WITH AN INERT GAS, WITH A REACTION MIXTURE CONTAINING AMMONIA, A CARBONYL COMPOUND AND A STRONG BASE, TH REACTION MIXTURE BEING SUBJECTED TO NO APPRECIABLE DELIBERATE AGITATION DURING THE REACTION.

Nov. 20, 1973 EFFREYs ETAL 3,773,831

PRoCESS FOR PRBPARING oZINES Fied A ri1 9, 1971 tJnited States Patent ()i1Ce 3,773,831 Pafenfed Nov. 20, 1973 3,773,831 4 PRoCESS EoR RREPARING AznIES Godfey vaughan Jefeys, suffon co1de1d, and coHn Emoff MarkS, Quom, England, aSSignots fo Eisons Linlifed, Su1fo1k, England 1ed Apr. 9, 1971, ser. No. 13z,740 c12iInS prioify, appio2on Geat Bifain, Apr. 10, 1070, 17,084/70 1nf. CL c07c ZZ9/00 U.s. cL Zso6 B 11 c1aimS ABSTRACT oE THE DISCLoSURE Azines afe prepaTed by feacting chlofine, dill1ted vvith an ineft gas, With a reaction 11ixt11Te containing aII1nonia, a caTbony1 compound and a StTong baSe, the Teaction mixtuTe being subiected to no appfeciab1e de1ibe1ate agitation during the feaction.

diStTibution of the chloran1ine thfonghout the Teaction mixture.

vve have now fonnd that it is not necesSaTy to agifate tho 1(action n1ixtuTe and that aS a resnlt pTobleInS assooiated vvith scale-np of a pfocoSS involving vigofous agita tion can be avoided. vve have also suTpfiSingly fo11nd that vvith the process of the invention it is poSSible to feduce the an1ount of baSe Tequifed during the production of azines to below the Z n1olaT pTopoTtions of n1oTe of oase pef n1olar proportion of chlorine hitherto consideTed necessaTy to enSure the prodoction of azines.

Accordingly, the pTesent i1ventiO11 felates fo a process fo1 pTepaTing azines Which compTiSes paSSing a gaS compTising free chloTine and an ine1t gaS throngh a feaction Inixture containing an1nlonia, a carbony1 coInpound and a strong base, the Teaction n1ixture being Subiected to no appfeciable de1ibeTate agitation during the Teaction.

The terIn delibeTate agitation iS USed herein fo denote agitation Which iS caTried out infentionany by an opefatof of the pfocesS It doeS Ilot includo the agftation vvhich occufs aS a neceSSary consequence of passing gaS though a Te ction mixture of of causing the feaction mixtnfe fo now through a vesseL The teTm incidental agitation Win be llSed to denote Such agitation as IIlay ariSe aS a con Sequenco of the opeTafion of the StepS of the process.

DeSirabIy the pToceSS of the invention is carTiod out n1efely by paSSing the chloTine-containing gas through the feaction InixtUTe vhich is I1ot f)eing subiected to v deHberate agitation.

Reaction (i) takeS place Within the gaS phaSe of the bubbles as they paSS through the Teaction mixtufe, the othef feactionS take p1ace in the 1iquid phaSe after tho chloramine has diffused out of the bubbles.

The ineft gaS/chlofine nlixturo Inay contain a vvide Tange of propoftions of ineft gas to chlorine. In general it iS pTeferable to uSe gas mixtUTes containing lTIore than of% but leSS than 10%, prefeTably less than 5%, ideany about 2 5, by volun1e of chloTine. The ineft gaS iI1 the Inixture may be any gaS which does not Teact to any appfeciable extent undeT the conditions of the pTocess. Suitable ineft gaSes inclnde gaSes of GmUp vIIIA of the Periodic Table, nitTogen and (pfeferably) air.

The cafbony1 coInpounds fo1 present USe include ko fones and aldehydes Which Inay have the genefal foTInula= vvheTein 1 iS an a1ky1 group, e.g. an alky1 group containing ffon1 1 to 6 carbon atoIns, of an aTy1 gToup; and 1 is hydrogen, alky1, e.g. an alky1 gTonp containin ffoIn 1 to 6 carbon aton1S, of an ary1 gToup, of together With R and the C:0 rou forms a c cloali hatic ketone. Specific exaIIlples of Suitab1e cafbony1 coInpoundS inolude acetaldehyde, pfopionaldehyde, benza1dehyde, acetone, diethylketone, n1ethylethylketone, Inethylisobutylketone, acetophenone and cyclohexanone. PfefeTred caTbony1 coInpoundS for pfesent nse afe acetone and n1ethy1ethy1 ketone.

Te feaction mixtnre i1 Which the feactions are car- Tied out lIlay coInpfise an excess of the carbony1 con1- pound. vvatef is produced duTing the pToceSS of the inven tion, and the Teaction II1ediuI1 Inay contain vvatef which may be present in fTo1 1 to 972, e.g. ffon1 10 to 977, by Weight of the reaction mediun1.

The Teaction medinm may exist aS eitheI' a tWo phaSe of a sing1e phaSe sySten1. 1f desired, an additive, Such as a loWer alcoho1, may be added to a two phaSe System in orde1 to obtain a single phase feaction nnediun1.

The feaction 111ixtllfe alSo contains an1Inonia and this conveniently takes the forn1 of annonia disSolved in the reaction nlediuf1. I) esirably the Teactioo n1ediun1 confainS as high a concentTation of an1nonia as poS ble and an1- monia gas iS desirably paSSed into the feacfion mixtu1o i11 order to nlaintain the conoentration of an1nlonia at as near SatuTation aS poSSible.

The process of the invention may be ca1'ried out meTe1y by bubbling the chlofine-containing gas thTough the feactioI1 medinm il1 Which the ammonia is dissolved. During itS passage through the reaction InixtuTe the chlofine iI the bubble Teacts vvith the aIn111onia in a gas phaSe Teaction to fofn1 chloranine vvhich then diffuses into the Teaction n1ixtue to initiate a seIieS of feactions leading to the pToduction of the azine. The foInlation of the chlofanline and pleted Within about 1 second and desifably a gaS fesidence tinle in the feaction IT1ixtIIfe of at leaSt 1 Second is pfovided.

AS indicated above, ammonia gas Inay alSo be fed into the Teaction mixtuTe. T11e pofpoSe of this is to replace aInn1onia conSun1ed dI1Ting the pToceSS of the invention and to n1aintain as high a concentfation as posSible of ammonia in the reaction Inixture. vVf1i1e the Whole of the Teaction nlixture fnay be nlaintained at Ilear Saturation wfth aInInonia, it iS prefefred to add afnnonfa gas at or neaf the point of entfy of the ch1ofinecontaining gas so aS to obtain a high loca1 concentTation of aInnlonia at thiS point, even though the feSt of the reaction ITixtllfo Inay not be Saturated vvith aInn1onia. T11is high 1oca1 concentration may be achieved by injecting ammonia gaS info the feaction miXtufe juSt below, Say 1 to 5 cm. beloW, the point of entry of the ch1ofine-containing gaS. Altef native1y, the aInInonia gas and the ch1ofinecontaini11g gaS nTay be fed dovvn concentTic fubeS to forn1 bubbles containing the gases at a tWi11 nozzle. In this lattef caso it i11 be appreciated that the afnInonia does not need to diffUSe into the chlofine bubbles befofe feaction can take place.

Theofetically, 3 InolS of amInonia afo reqIlifed dur ing the pfodnction of one nlo1 of azine ffom one fflol of chlorine. However, it is desirable that the ammonia to ohlorine Inolaf Tatio is above 10:1, prefeTably Within the Tange =1to :1.

The theoretica1 amount of cafbony1 coInpound fequifed to feact With the hydfazine produced ffon1 one mo1 of chloTine is 2 I1o1S. Fof continuous operation in an aque ouS IIledi11In it is pfefeffed to uSe 3-5 I11ols of cafbony1 compound per mo1 of chlofine; but for batch operation this nlay be Teduced to 2 n1ols per n1o1 of ch1oTine. I1ov over, a Iarge excesS of cafbony1 compound ITlay be uSed if desifed, aS is the case whefe the feaction Inedium is p1o vided by the carbony1 con1pound. vvith an excess of cafbony1 con1pound, satuTation of the reaction nlediun1 vvith amnlonia vvin usually enSufe that an adequate excesS of amInonia fS alSo pfesent ata11tiInes.

5t leaSt one InolaT pfopoffion of Strong baSe iS fo quiTed foI' each n1o1 of ohIofine gaS fed into the feaction Systen1. It is desirable alSo fo pfovide su0ioient stTong base to neotTalise the anln1onia chlofide produced. Since the USe of excessive aInounts of stTong baSe IIlay Tes111t in deco1poSition of the chlofalTline, the an1ount of Strong baSe is prefefably belovv tvvo Inolar pTopoftions. Thus ffom 12 to 2.0 n1olS of ase may be used per mo1 of chlofine. The amonnt of base Tequifed to nentraHSe the aIn moniUm chlofide Which disSo1ves in the feaction 1ixtuTe nlay be coffelated to the pII of the reaction n]ixtuTe at a given ten1perature, and aIT1Inonia concentTation and IneaSuronlent of pII thus offeTS a convenient Inethod fof n1onitofing the amount of baSe TequiTed. Thns at a tempefatuTe of abont 55 c. and an aInInonia concentration of 7% by Weight, the pH of fhe feaction n1ixtofo may be ffon1 100 to 12.5, and is pfefefably 110 to 11.5. It Should be noted that, vvhefeas if1 eaflier processeS vvith vigofons agitation SubStantia11y a11 the aInn1oniun1 ch1o ride fofIned vvas diSSolved in the feaction Inixtnfe, Wo have fo11I1(ithati11the abSence of delibefate agitation a SubStan tial pToportion of the aInn1oninn1 chloride iS entrained in the gas bubbles and Te1T1oved ffoIn the feaction systeIn.

The stfong base is a baso vvhich iS capable of I1e11tfalising ammonium ch1ofide. Suitable strong bases includo alkali-D1eta1 and alka1ine-eafth fnetal hydfoXidos, o.g. ca1 ci11In, n1agneSiun, potaSsiun1 or sodium hydfoXide; and quaternafy baSeS Such aS anion oxchango TesinS, tetfan1ethylaInn1oninn1 hydroxide, benzyltfiInethylanInoniun hydfoxide atld the like. Fof TeasonS of econoIny, sodiUn1 hydToxide of calciun1 hydroxido aro genefaHy the pfe feffed baSes The stfong base n1ay be pfesent ab initio in the feaction n1ixtufe, but iS pTefefably added at an ap pfopTiate fate siII1111taIleouS1y vith the ch1oTine-contain ing gas. l)eSifab1y the Strong baSe is added aS an aque ous solution.

TT1e process of the invontion 1flay bo oaffied out as a batch pfocoSS, in vvhich case tho propoftions of baSo, anInonia and caTbony1 con1pound afe related fo the tota1 amonnt of ch1ofine to be fed fo the feaction miXtufe; of as a continuous procesS vvhero the pfoportions are Telated to tho fato of f1ov of the vafiouS feactantS thfongh the feaction syStem. 11i1e diffusion of aInn1onia into the chlorine-containing gas bubbles, the fornlation of the chloTaInine and itS diffusion into the 1iquid phaSe Inay oc cuf compafatively quickly, the foactions initiated in tho liquid phase by the chloran1ine may requife a longe1 pe fiod to proceed to coInplefion. It iS therefofe desiTed that tho liquid phaSe have a conlpatatively 1ong reaction tin1e befofe being tTeated fI1ftheT, e.g. ffon1 10 fo 20 II1inutes. It vi1l be a pfociated that longef feaction tin1eS than theSe may be 11Sed if deSed and that not a11 the feaction need take place in a single feaction vessel but that aftef an initia1 contact stage betWeen the liquid phase and ch10- rinecontaining gaS, the 1iquid phase nay be paSSed to one of n1ofe othef vesSelS in vvhich Teaction is conlpleted,

As indicated abovo, the procosS of the invontion is caf ried out by paSSing the chlofine-containing gas, optionany also ommonia gaS and st1ong baSe, into a feaction Inediun1 oontai1ing a oafbonyl conlpound and an1onia. Tho paSS ing of the gas InixtUTo and the snbsequent Teactions nlay be carfied out at any temperatuTe up to the boiling point of the Hquid phaSo, pfeferably at from 15 to 55 C. If desifed the addition of the gas and the subSequont oac tionS Inay be caffied out undef pfossuTe, e.g. at up to 20 atInoSpheres gaugo, but this is not genefally necossary.

The pToduct of tho pfoceSS of tho invontioI1 may be fecoveTod ffon1 tho foaction n1ixtI1ro and 1)1rified if dosired by conventional techniques. I(eSidual foactantS and by-pfod11cts nlay be rocovefed and fe-11Sod if doSired.

The process Win noW be inustrated by Way of examp1e With reference to the accompanying dTaWing Which is a diagfan11atic vievv of a suitab1e feaction veSSeL The foaction voSSol ooInprisos a vertica1 cloSed oyIindfica1 glaSS tovvef. The base of the tovver is provided With an inlot fof tho reactant cafbony1 coInpound/vvafef oix tuTe. In the basa1 portion of the tover aro provided an in1et for stfong aqueous baSe, a nozz1o fof gaseous am Inonfa and a noZzle for the ineft gaS/chlofine IIlitllfo, theSe nozzles boing positioned a1ong the axis of the toWer in the ordof given. Near the top of the toWe1 is a pfoduct outlet and the top oloSod end iS providod vvith a gaS offiu ent pipe.

EXAMPLE A solution of IIlothy1ethy1ketono 10% vv./W. in vvatef iS pumped to a toWer, aS deScribed above, 6 incheS in dian1- oter and 12 inches high, at a rafo of 18 1itTes/hour. This gives a liquid fesidenco tiIIle of 'about 20 11iIlutes. T,ho tenlpeTature of the so111tion in the tovvef is Inaintained at 55 ()nce the tovver is fi11ed vvith soll1tion, alI111onfa gas is paSSed thfough at a Tate sunfoient to enSuro satnfation of the solution. At 55 it has been found that an on1- monia fee(1 fate of 7% W./W- based on the Water inpnt to the toWer is Satisfactory.

(:h1ofino iS then fed to tho tovver aS a 1ixtufe of 98% v./v. nitfogen and 2% v./v. chlofino at a tota1 gas Tate of 1120 1itreS/hf. SiIIlulfanoously aquoous SodiuIn hy droxide (5 W./W. NaoH) is fed to the toWef at a rate equiva1ent to1.5 Inols sodfum hydfoxido pef mo1 of chlorine foed.

TJnder theso conditions the ovefa11 yield of nlethylethy1 ketono azino vas baSed on tho chlofine feed to the toWer. No stirrer of othet a itation WaS uSed.

vve clain1= 1. In a prooess fo1' prepadng azinos Which con1prises paSSing a gas Inixture containing ffee chlorino and an inert gas through an aqueous feaction IIixturo fofoled ffofn ammonia, a st1ong be and a oa1bony1 co1npound of the foTmula Whofoin R iS alky1 of 1 to 6 cafbon atoms of pheny1 and 1 is hydTogen, alkyl of 1 to 6 carbo11 atoms or phenyL of R and R togetHer Wit11 the ca1bony1 group fonn a cycloali hatic ketone, the iII1p1oven1ent WheTei1 the only SubStantial agitation of the feaction 111ixt111e iS cauSed by the paSSage of the gas 111ixture.

2. A p1ooeSS accofding to clain1 1 Wherein the inert gas is Selected fro111 gases of Gmup vIIIA of the Pe1iodic Table, nit1ogen and air.

3. rocess accordin to daim 1 WheTein the catbon 1 compound iS Selected fron1 acetaldehyde, pfopionalde hyde, benzaldehyde, nlethy1 ethy1 ketone, diethylketone, :nethy1 isobuty1 ketone, acetophenone, cyclohexanone and aoetone,

4. A rocess accordin t() claim 1 Wherein the teaction n1ixtute com Tises an excess of the carbon 1com ound.

5. A process according to clain1 1 Wherein the Teaction n1edinn1 contai11S 1 to 97% by Weight of wate1.

11. A Tocess accordin t() claiIn 1 Wherein the tesidence ti1ne of the gas 111 the reaction 111ixtl11e is at leaSt 1 seoond.

7. A pTocoss aocofding to daim 1 Wheroi11 a111.o1o11ia gaS iS fed to the 1oaction mixture at a p,oint adiacent to the point of entry of the gas mixture.

8. A TocesS accordin to clain1 1 vvherein the mola1 Tatio of an1Inonia t() chlorine iS greate1 than 10:1 and less than 20;1.

9. A roceSS accDTdin to claim 1 herein the stron baSe is Selected ffom alkali n1etal hydroxides, alkali11e earth metal hydToXides, and quaternafy ammoniun1 baSes.

10. A process according to clai111 vvherein the strong base is Selected ffon1 sodiun1 hydToxide and calciu1 hy droxide.

11. A pTocesS according to olaim 1 Wherein the 1eaction is carried out at a teInperature of 1 to S5 C.

ReferenceS Ced UNITED STATES PATENTS 3,41,88Z 12/1968 Ienkins et al Z6oS66 B 3,3 8Z,041 S/1968 Neodhan1 et aL Z566 B x 3,Z7,7S3 9/1970 Needham of aL 26066 B FoREIGN PATENTS So7,39Z 11/19S4 Canada 23190 R HowARD T. MARS, PriInar Exanliner M. vv. GLYNN, ASSistant Exan1ine1 U.s. CL X R, Z3-19o R 

